Means for forming twist-drills.



A. WARD.

MEANS FOR FORMING TWIST DRILLS.

Patented Mar. 1, 1910.

022 m.- wml w A ma UNITED STATES PATENT OFFICE.

ALVIN WARD, OF CLEVELAND, OHIO, ASSIGNOR TO THE CLEVELAND TWIST DRILLCOMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

MEANS FOR FORMING TWIST-DRILLS.

Specification of Letters Patent.

Ilatented Mar. 1, 1910.

Application fi1ed J uly 1, 1909. Serial No. 505,351.

To all whom it may concern:

Be it known that I, ALVIN \VARD, a citizen of the United States,resident of Cleveland, county of Cuyahoga, and State of Ohio, haveinvented a new and useful Improvement in Means for Forming Twist-Drills,of which the following is a specification, the principle of theinvention being herein explained and the best mode in which I havecontemplated applying that principle, so as to distinguish it from otherinventions.

My invention relates to means for forming twist drills, and particularlyto the means employed in the method for forming twist drills describedand claimed in my pending application filed February 14:, 1008, SerialNo. 415,981, for method of forming twist drills.

The said invention consists of means hereinafter fully described andparticularly set forth in the claims.

The annexed drawing and the following description set forth in detailcertain means embodying my invention, the disclosed means, however,constituting but one of various mechanical forms in which the principleof the invention may be applied.

In said annexed drawing: Figure 1 is a plan of one of the diesconstituting part of my invention. Fig. 2 is an end elevation of suchdie, and Fig. 3 is a cross sectional view taken upon the plane indicatedby line III-III in Fig. 1. Fig. 4 is an elevation of a blank rod, andFig. 5 is a similar view of the finished product resulting from theoperation of my improved dies.

The die block A is formed with a semicylindrical depression a which isangularly traversed by a projection a, itself of semicylindrical crosssection. This projection is made of a height substantially equal toabout one-half the extreme depth of the depression a as shown in Fig. 2and its base intersects the cylindrical surface of the depression. Thecross-sectional area of the depression a is made such that when theblank rod is laid therein and upon the projection a only a small amountof lateral play is permitted for a purpose hereinafter specified.

A similar depression a is formed upon another part of the block whoseextreme portions are made accurately of a semicylindrical form whosecross-sectional area is made exactly equal to one-half of the circularcross-sectional area of the required finished forging. An angularlyplaced portion a of the depression a is made of greater depth than theend port-ions of the depression a as shown in Fig. 2-3, so as to presenta greater cross sectional area on a plane having an angularitysubstantially equal to the angle of the required flute and indicated bythe line w-rc, Fig. 1. Protruding upwardly from this enlarged portion ofthe depression is a projection a. which is also angularly placed withreference to the depressions axis as shown and is furthermore ofsen'ii-oylindrical cross-section, the middle part of such cross sectioncorresponding substantially to the cross-section of the desired finishedforging. This projection a is furthermore of greater height than that ofprojection a.

In carrying out my improved process, the die block A is placed in asuitable foundation to form an anvil and a similar die block providedwith depressions and projections exactly similar to those just describedbut. reversed to assume the position indicated in dotted lines in Fig.1, is secured to the head of a suitable drop, trip or steam hammer.

The blank to be operated upon is heated to a suitable temperature andthen placed in the depression a and upon the projection a so as to bringthe latter in a position which will be occupied by that end of theflutes adjacent to the shank of the drill. In this position, (see dottedlines Fig. 1), as was previously stated, only a small amount of lateralmovement of the blank is permitted so that the projection a will beproperly centered with relation to the blank. The hammer is now operatedto bring the other portion of the die down upon the top of the blank,whereby the projection a, and the corresponding projection of the otherportion of the die are caused to make two oppositely disposeddepressions of opposite angularity, as will be readily understood. Theblank is then given a helical movement in the direction of its axis andthe hammering operation continued, the projection a being used as aguide. Two oppositely disposed fiutes are thus formed which have not,however, their final depth or form. The blank so impressed is nowtransferred to the groove a of the die block and placed therein so as tocause the projection a to engage the flutes formed in the abovedescribedoperation. The upper movable die is now caused to descend upon the blankin a number of successive blows so as to further enlarge the impressionpreviously formed. Such action produces a projection having the contourof the depressed portion a of the depression a and the projectiona, themetal expanding into the portion ar After the required number of blowshave been delivered to produce this contour, the blank is turned so asto impart thereto a helical movement in the direction of the blanksaxis, the projection a being used as a guide for such purpose. Thisbrings a succeeding portion of the blank into the field of operation ofthe die and the required number of blows are now struck to produce aresult upon this portion of the blank such as above described. In thismanner every portion of the blank may be presented to the action of thedie and two continuous helical and oppositely disposed flutes therebyformed upon the blank to produce the finished product.

The expanded portions of the blank after being formed are brought intothe field of action of the cylindrical end portions of the depression aand thereby caused to assume the exact required size. The completedforging is now placed in a straightening die to give it a rectilinearform. All surfaces of the depression a are rounded slightly as shown andparticularly those surfaces which form the connection between thecylindrical portion thereof and the depressed portion (0* thereof sothat the product of the above described operation will on completionpresent a smooth and uniform appearance. The action of the cylindricalend portions of the depression is such as to compress the enlargedportion formed in the vicinity of the projection 05- which results inthe slight contraction of the outer portion of the flutes. Thiscontraction permits the edges of the flutes to present a sharp line whenthe drill is ground to its final exterior form.

Having fully described my invention, what I claim therefor and desire tosecure by Letters Patent is:

1. In means for forging twist drills or the like, a die element with asemi-cylindrical depression traversed angularly by a projection, thecross-section of such depression being enlarged adjacent to the base ofsaid projection.

2. In means for forging twist drills or the like, a die member formedwith a semicylindrical depression traversed angularly by a projection,the cross-section of said depression being enlarged adjacent to the baseof said projection; the area of the cross section of the remainingportion of the depression being substantially equal to one-half of thecircular cross-sectional area of the finished drill.

Signed by me, this th day of J une, 1909.

ALVIN WARD.

Attested by GUR'r B. MUELLER, K. F. JUENGLING.

